testsuite/libffi.call/many.c: Avoid spurious failure due to excess precision
testsuite/libffi.call/many.c: Avoid spurious failure due to excess precision

The test case testsuite/libffi.call/many.c can spuriously fail due to
excess floating-point precision.  Instrumenting it with some printf
calls shows differences well above FLT_EPSILON.  (Note when
instrumenting it that multiple computations of the difference, such as
one in a print and another in the conditional, may produce different
results.)

Rather than complicating the test suite with architecture-specific flags
to avoid excess precision, just simplify the floating-point computation
to avoid a dependency on potential excess precision.

Distrotech/libffi,Pan7/libffi,Pan7/libffi,s1341/libffi,plicease/libffi,s1341/libffi,joshtriplett/libffi,bgarrels/libffi,plicease/libffi,nmav/libffi,bgarrels/libffi,Pan7/libffi,biosbits/libffi,johne53/MB3Libffi,johne53/MB3Libffi,plicease/libffi,plicease/libffi,johne53/MB3Libffi,s1341/libffi,rth7680/libffi,joshtriplett/libffi,biosbits/libffi,Pan7/libffi,Distrotech/libffi,rth7680/libffi,joshtriplett/libffi,rth7680/libffi,nmav/libffi,bgarrels/libffi,biosbits/libffi,Distrotech/libffi,s1341/libffi,bgarrels/libffi,johne53/MB3Libffi,rth7680/libffi,joshtriplett/libffi,nmav/libffi,johne53/MB3Libffi,Distrotech/libffi,nmav/libffi,biosbits/libffi